Low dose aspirin and compression does not increase healing of VLU

Low dose aspirin does not increase healing of venous leg ulcers (VLU) when used in addition to effective compression, according to researchers from the University of Auckland, New Zealand. The study, funded by the New Zealand Health Research Council and conducted by researchers at the University's National Institute for Health Innovation, found 150mg aspirin a day in addition to compression bandaging did not increase venous ulcer healing.

"The outcomes mean people who have a venous leg ulcer and who have to take aspirin for other reasons still heal at a pretty good rate if they use compression,” said study lead, Associate Professor Andrew Jull. "We will shortly be getting in touch with the participants to let them and their doctors know which drug they were taking. We remain very grateful to those people who came forward to be part of the study – without them we would not have the evidence to help others."

The outcomes from the Aspirin4VLU trial were published in the paper, ‘Low dose aspirin as adjuvant treatment for venous leg ulceration: pragmatic, randomised, double blind, placebo controlled trial (Aspirin4VLU)’, in the British Medical Journal. Aspirin4VLU is the world's largest aspirin trial yet conducted for patients with venous ulcers and the only trial of low dose aspirin.

The objective of the trial was to determine the effect of low dose aspirin on ulcer healing in patients with venous leg ulcers. The main outcome measure was the primary outcome was time to complete healing of the reference ulcer (largest ulcer if more than one ulcer was present). Secondary outcomes included proportion of participants healed, change in ulcer area, change in health-related quality of life, and adverse events. The analysis was by intention to treat.

In total, 251 adults with venous leg ulcers who could safely be treated with aspirin or placebo were recruited into the trial - 125 were randomised to aspirin and 126 to placebo. Patients in the aspirin group were given 150mg oral aspirin daily vs. matching placebo for up to 24 weeks treatment, with compression therapy as standard background treatment.

Outcomes

The median number of days to healing of the reference ulcer was 77 in the aspirin group and 69 in the placebo group (hazard ratio 0.85, 95% confidence interval 0.64 to 1.13, p=0.25, Figure 1). The number of participants healed at the endpoint was 88 (70%) in the aspirin group and 101 (80%) in the placebo group (risk difference −9.8%, 95% confidence interval −20.4% to 0.9%, p=0.07).

Figure 1: Kaplan-Meier plot for time to complete healing of venous leg ulcer by trial treatment group

Estimated change in ulcer area was 4.1cm2 in the aspirin group and 4.8cm2 in the placebo group (mean difference −0.7 cm2, 95% confidence interval −1.9 to 0.5 cm2, p=0.25). There were forty adverse events that occurred among 29 participants in the aspirin group and 37 adverse events among 27 participants in the placebo group (incidence rate ratio 1.1, 95% confidence interval 0.7 to 1.7, p=0.71).

“Low dose aspirin does not increase healing of venous leg ulcers when used in addition to effective compression,” the authors concluded. “Indeed, the direction of effect seems to be the opposite of that in previous trials. Explanations may lie with bias in previous trials or with the dose of aspirin. Until the evidence base has been expanded by anticipated reports from new trials evaluating 300mg doses, aspirin should not be used as an adjuvant for the treatment of venous leg ulcers.”